Calculus 3 : Vectors and Vector Operations

Study concepts, example questions & explanations for Calculus 3

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Example Questions

Example Question #24 : Vector Addition

Find the sum of the vectors:

\(\displaystyle \left \langle 3, 2, e^2 \right \rangle + \left \langle 0, 0, 1 \right \rangle + \left \langle 0, 0, 0 \right \rangle\)

Possible Answers:

\(\displaystyle \left \langle 3, 0, e^2+1 \right \rangle\)

\(\displaystyle \left \langle 0, 2, 0 \right \rangle\)

\(\displaystyle \left \langle 0, 0, 0 \right \rangle\)

\(\displaystyle \left \langle 3, 2, e^2+1 \right \rangle\)

Correct answer:

\(\displaystyle \left \langle 3, 2, e^2+1 \right \rangle\)

Explanation:

To add vectors, we simply add their components. For example, \(\displaystyle \left \langle x, y \right \rangle+\left \langle a, b \right \rangle=\left \langle x+a, y+b \right \rangle\).

Our answer is

\(\displaystyle \left \langle 3, 2, e^2+1 \right \rangle\)

Example Question #25 : Vector Addition

Compute the sum of the vectors \(\displaystyle \left \langle 0,-2,1\right \rangle\) and \(\displaystyle \left \langle 0,3,-7\right \rangle\).

Possible Answers:

\(\displaystyle \left \langle 0,-1,6\right \rangle\)

\(\displaystyle \left \langle -1,0,0\right \rangle\)

\(\displaystyle \left \langle 0,1,-6\right \rangle\)

\(\displaystyle \left \langle 2,-1,0\right \rangle\)

Correct answer:

\(\displaystyle \left \langle 0,1,-6\right \rangle\)

Explanation:

The formula for the sum of two vectors a and b is \(\displaystyle a+b=\left \langle a_1+b_1,a_2+b_2,a_3+b_3\right \rangle\). Using the numbers we have, we get the resultant as \(\displaystyle \left \langle 0+0,-2+3,1-7\right \rangle=\left \langle 0,1,-6\right \rangle\).

Example Question #26 : Vector Addition

Solve:

\(\displaystyle \left \langle 2, 5\cos^2(x), 0\right \rangle + \left \langle y, 5\sin^2(x), 2\right \rangle\)

Possible Answers:

\(\displaystyle \left \langle 2+y, 1, 2\right \rangle\)

\(\displaystyle \left \langle 2+y, 5, 2\right \rangle\)

\(\displaystyle \left \langle 2y, 25\sin^2(x)\cos^2(x), 0\right \rangle\)

\(\displaystyle 9+y\)

Correct answer:

\(\displaystyle \left \langle 2+y, 5, 2\right \rangle\)

Explanation:

To add vectors, we simply add the components. For example:

\(\displaystyle \left \langle a, b, c\right \rangle+ \left \langle x, y, z\right \rangle= \left \langle ax+by+cz\right \rangle\)

Our final answer is

\(\displaystyle \left \langle 2+y, 5, 2\right \rangle\)

Note that a Pythagorean identity was used when combining the "y" terms.

Example Question #231 : Vectors And Vector Operations

Solve:

\(\displaystyle \left \langle 5, 3x+5\right \rangle+\left \langle e^x, z\right \rangle\)

Possible Answers:

\(\displaystyle \left \langle 5+e^x, 3x+5+z\right \rangle\)

\(\displaystyle \left \langle 5e^x, z(3x+5)\right \rangle\)

\(\displaystyle \left \langle 5+e^x, 3x+z\right \rangle\)

\(\displaystyle 10+e^x+3x+z\)

Correct answer:

\(\displaystyle \left \langle 5+e^x, 3x+5+z\right \rangle\)

Explanation:

To add two vectors, we simply add the corresponding components (for example, \(\displaystyle \left \langle a, b\right \rangle+ \left \langle c, d\right \rangle= \left \langle a+c, b+d\right \rangle\))

Our answer is therefore

\(\displaystyle \left \langle 5+e^x, 3x+5+z\right \rangle\)

 

Example Question #28 : Vector Addition

Find the sum of the two vectors.

\(\displaystyle u=< 1,5,7>\)

\(\displaystyle v=< 8,1,3>\)

Possible Answers:

\(\displaystyle < 9,6,10>\)

\(\displaystyle < 9,6,5>\)

\(\displaystyle < 3,6,5>\)

\(\displaystyle < -5, 4, 4>\)

Correct answer:

\(\displaystyle < 9,6,10>\)

Explanation:

The sum of two vectors 

\(\displaystyle a=< a_1, a_2, a_3>\)

\(\displaystyle b=< b_1, b_2, b_3>\)

is defined as 

\(\displaystyle a+b=< a_1+b_1, a_2+b_2, a_3+b_3>\)

For the vectors in this problem

\(\displaystyle u+v=< 1+8, 5+1, 7+3>=< 9, 6, 10>\)

Example Question #29 : Vector Addition

Find the sum of the two vectors, \(\displaystyle u+v\).

\(\displaystyle u=< 2,3,7>\)

\(\displaystyle v=< 4,5,2>\)

Possible Answers:

\(\displaystyle < 6,8,9>\)

\(\displaystyle < 5,7,12>\)

\(\displaystyle < -2,-2,5>\)

\(\displaystyle < 4,1,3>\)

Correct answer:

\(\displaystyle < 6,8,9>\)

Explanation:

The sum of two vectors 

\(\displaystyle a=< a_1, a_2, a_3>\)

\(\displaystyle b=< b_1, b_2, b_3>\)

is defined as 

\(\displaystyle a+b=< a_1+b_1, a_2+b_2, a_3+b_3>\)

For the vectors in this problem

\(\displaystyle u+v=< 2+4, 3+5, 7+2>=< 6, 8, 9>\)

Example Question #30 : Vector Addition

Find the difference between \(\displaystyle \left \langle 30,15,100\right \rangle\) and \(\displaystyle \left \langle 2,25,99\right \rangle\).

Possible Answers:

\(\displaystyle \left \langle 28,-10,1\right \rangle\)

\(\displaystyle \left \langle 29,10,3\right \rangle\)

\(\displaystyle \left \langle 15,10,1\right \rangle\)

\(\displaystyle \left \langle 32,40,199\right \rangle\)

Correct answer:

\(\displaystyle \left \langle 28,-10,1\right \rangle\)

Explanation:

The formula for the difference of vectors is 

\(\displaystyle \left \langle x_1,x_2,x_3\right \rangle-\left \langle y_1,y_2,y_3\right \rangle=\left \langle x_1-y_1,x_2-y_2,x_3-y_3\right \rangle\)

Using the vectors given, we get 

\(\displaystyle \left \langle 30-2,15-25,100-99\right \rangle=\left \langle 28,-10,1\right \rangle\).

Example Question #31 : Vector Addition

Find the sum of the vectors \(\displaystyle \left \langle 2,0,5\right \rangle\) and \(\displaystyle \left \langle 1,2,3\right \rangle\).

Possible Answers:

\(\displaystyle \left \langle 3,2,8\right \rangle\)

\(\displaystyle \left \langle 1,1,5\right \rangle\)

\(\displaystyle \left \langle 1,9,6\right \rangle\)

\(\displaystyle \left \langle 1,7,3\right \rangle\)

Correct answer:

\(\displaystyle \left \langle 3,2,8\right \rangle\)

Explanation:

The formula for adding vectors is 

\(\displaystyle a+b=\left \langle a_1+b_1,a_2+b_2,a_3+b_3\right \rangle\).

Plugging in the values we were given, we get 

\(\displaystyle \left \langle (2+1),(0+2),(5+3)\right \rangle=\left \langle 3,2,8\right \rangle\)

Example Question #32 : Vector Addition

What is the sum of the vectors \(\displaystyle \left \langle 3,9,100\right \rangle\) and \(\displaystyle \left \langle 2,15,99\right \rangle\).

Possible Answers:

\(\displaystyle 224\)

\(\displaystyle \left \langle 5,23,100\right \rangle\)

\(\displaystyle \left \langle 2,18,100\right \rangle\)

\(\displaystyle \left \langle 5,24,199\right \rangle\)

Correct answer:

\(\displaystyle \left \langle 5,24,199\right \rangle\)

Explanation:

The formula for adding vectors is 

\(\displaystyle a+b=\left \langle a_1+b_1,a_2+b_2,a_3+b_3\right \rangle\).

Plugging in the values we were given, we get 

\(\displaystyle \left \langle (3+2),(9+15),(100+99)\right \rangle=\left \langle 5,24,199\right \rangle\)

 
 

 

Example Question #231 : Vectors And Vector Operations

\(\displaystyle \vec{a}=6i+4j-2k\) and \(\displaystyle \vec{b}=-3i-4j+7k\). Find \(\displaystyle \vec{a}+\vec{b}\)

Possible Answers:

\(\displaystyle 3i+5k\)

\(\displaystyle 3i\)

\(\displaystyle -9i-8j-9k\)

\(\displaystyle 0\)

\(\displaystyle 8\)

Correct answer:

\(\displaystyle 3i+5k\)

Explanation:

\(\displaystyle \vec{a}+\vec{b}=(6-3)i+(4-4)j+(-2+7)k=3i+0j+5k=3i+5k\)

 

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